Stem mounted 1-1/2" 'fine' wire wheel brush with 1/4" (6.35mm) hex shank. designed for easy access into narrow holes and confined areas. crimped style for light to medium duty applications. removes rust, scale and paint in hard to reach areas. use with any 1/4" (6.35mm) diameter electric power drills or 01990 pneumatic (air) drill. diameter: 1-1/2" shank: 1/4" hex wire size: .008" (.203mm) rpm: